Abstract: On the foundation of the forming process observation of cemented filling body and roof destruction statistics,revealing the structure of filling body and destruction form,then study the structure of downward drift and stress characteristic,proposing rectangular section simple beam model of drift structure in downward drift stoping.Using elasticity theory analysis law,infers the biggest bending stress expression of drift roof,proposing appraisal method of filling body quality,then after the practice proof is reasonable,providing a quantitative quality control method to the production site.At the same time,it also for further reduces the material consumption,enhanced filling body quality to provide the main theory basis.